“One of the things that really resonated with investors… was that Cardiff as a events city is second only to London but, also, the Welsh brand which made us unique among the other seven franchises,” he said.
Mr Rhydderch-Roberts said Wales as a nation could do more to improve its branding.
“What are we selling here in Wales because sometimes our image is rather tarnished by 20 mile an hour speed limits for example,” he said, referring to the Welsh government’s controversial decision to reduce speed limits across the country.
“Those kind of things… the noise in the background… prevents us from looking at the real positives.”
The Welsh government has confirmed its international investment summit will take place in Newport on 1 December.
The first minister told BBC Wales on Friday that she was “looking for billions of pounds of investment to come in and thousands of jobs to be delivered”.
